Instruments having endoscopic or optical assemblies have been extensively used by surgeons to provide an internal view of an organ, body passage or lumen of a patient during a surgical procedure. Such instruments usually include working elements, such as forceps, scissors, probes and the like, to enable the surgeon to manipulate body tissue during the surgical procedure. Such instruments have been used in a wide range of surgical and microsurgical procedures including, for example, operations on small intracranial vessels, extirpation on small pituitary adenomas, low-risk clipping of intracranial aneurysms, removal of extensive pituitary adenomas with conservation of the infundibulum and the small hypothalamic vessels as well as the preservation of the facial nerve, and preservation of the cochlear nerve in connection with extirpation of acoustic neuromas.
There are, however, drawbacks associated with the use of surgical instruments having endoscopic assemblies. For example, the endoscopes tend to interfere with the surgical procedure and affect the control and tactile feel imparted by the instrument to the surgeon. Additionally, the endoscope may be difficult to remove or replace, and, as a result, the surgical instrument may have a limited life and may be difficult and costly to sterilize.
For example, surgical instruments have been used that include endoscopes having channels that receive the surgical tools. Such instruments tend to be large and difficult to work with, however. The instruments are difficult to control and the tactile feel of the tools is significantly affected by the endoscopes.
Surgical instruments that have the endoscopes mounted within the shaft of the instrument often tend to be relatively large in diameter which limits their use. Since the endoscope cannot be removed, the entire instrument must be replaced if the endoscope becomes damaged. Also, it is likely that the instrument cannot be heat sterilized since endoscopes can be damaged by exposure to heat.
Those surgical instruments that include an endoscope attached to the exterior of the shaft of the instrument tend to be awkward because the endoscopes protrude from the shaft of the instrument and tend to interfere with the surgical procedure and limit the surgeon's ability to move or twist the instrument during surgery. Also, because precise alignment is required between the endoscope and the working element, the endoscope cannot be replaced quickly and easily if it becomes damaged or if the instrument is being heat sterilized.
Additionally, rigid endoscopes are often used which are difficult to work with and expensive to manufacture because the instruments require precise alignment of the endoscope. Since surgical instruments with rigid endoscopes cannot be bent, they also limit the surgeon's ability to gain access to many areas of the body to be worked on.
Although it is known to use flexible endoscopes to enable access to parts of the body that are not accessible with rigid instruments, it often is difficult to position the working end of the instrument due to the construction of the device. A surgical instrument having a distal end that cannot be precisely maneuvered tends to interrupt a surgeon's tactile feel and ability to control the working element of the instrument and the tissue being manipulated.
For many of the same reasons described above, surgical instruments having irrigation systems also have limitations. Irrigation systems tend to interfere with the surgical procedure and affect the control and tactile feel of surgical instruments because they tend to protrude from the instrument and impose forces on the instruments.
Accordingly, what is needed is a surgical instrument having an optical assembly that does not interfere with the surgical procedure and does not substantially affect the control and tactile feel of the instrument. Such an instrument should provide improved viewing of the surgical procedure. The optical assembly should also preferably be readily and removably secured to a shaft of the instrument so that the instrument can be assembled readily and easily and so that the optical assembly can be removed or replaced readily and easily. The optical assembly also should be flexible to facilitate quick and easy assembly, even if the handle of the instrument is offset relative to the shaft or if the shaft is curved. The device should also be small in cross section to provide for easy access to the tissue and improved tactile feel. Desirably, the device also should preferably include a convenient irrigation means for providing an irrigation fluid to the surgical area. The present invention meets these desires.